/*       $KAME: md5.c,v 1.3 2000/02/22 14:01:17 itojun Exp $       */

/*
 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *      notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *      notice, this list of conditions and the following disclaimer in the
 *      documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the project nor the names of its contributors
 *      may be used to endorse or promote products derived from this software
 *      without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * contrib/pgcrypto/md5.c
 */

#include "postgres.h"

#include <sys/param.h>

#include "md5.h"

#define SHIFT(X, s) (((X) << (s)) | ((X) >> (32 - (s))))

#define F(X, Y, Z) (((X) & (Y)) | ((~X) & (Z)))
#define G(X, Y, Z) (((X) & (Z)) | ((Y) & (~Z)))
#define H(X, Y, Z) ((X) ^ (Y) ^ (Z))
#define I(X, Y, Z) ((Y) ^ ((X) | (~Z)))

#define ROUND1(a, b, c, d, k, s, i) \
do { \
    (a) = (a) + F((b), (c), (d)) + X[(k)] + T[(i)]; \
    (a) = SHIFT((a), (s)); \
    (a) = (b) + (a); \
} while (0)

#define ROUND2(a, b, c, d, k, s, i) \
do { \
    (a) = (a) + G((b), (c), (d)) + X[(k)] + T[(i)]; \
    (a) = SHIFT((a), (s)); \
    (a) = (b) + (a); \
} while (0)

#define ROUND3(a, b, c, d, k, s, i) \
do { \
    (a) = (a) + H((b), (c), (d)) + X[(k)] + T[(i)]; \
    (a) = SHIFT((a), (s)); \
    (a) = (b) + (a); \
} while (0)

#define ROUND4(a, b, c, d, k, s, i) \
do { \
    (a) = (a) + I((b), (c), (d)) + X[(k)] + T[(i)]; \
    (a) = SHIFT((a), (s)); \
    (a) = (b) + (a); \
} while (0)

#define Sa     7
#define Sb    12
#define Sc    17
#define Sd    22

#define Se     5
#define Sf     9
#define Sg    14
#define Sh    20

#define Si     4
#define Sj    11
#define Sk    16
#define Sl    23

#define Sm     6
#define Sn    10
#define So    15
#define Sp    21

#define MD5_A0    0x67452301
#define MD5_B0    0xefcdab89
#define MD5_C0    0x98badcfe
#define MD5_D0    0x10325476

/* Integer part of 4294967296 times abs(sin(i)), where i is in radians. */
static const uint32 T[65] = {
    0,
    0xd76aa478, 0xe8c7b756, 0x242070db, 0xc1bdceee,
    0xf57c0faf, 0x4787c62a, 0xa8304613, 0xfd469501,
    0x698098d8, 0x8b44f7af, 0xffff5bb1, 0x895cd7be,
    0x6b901122, 0xfd987193, 0xa679438e, 0x49b40821,

    0xf61e2562, 0xc040b340, 0x265e5a51, 0xe9b6c7aa,
    0xd62f105d, 0x2441453, 0xd8a1e681, 0xe7d3fbc8,
    0x21e1cde6, 0xc33707d6, 0xf4d50d87, 0x455a14ed,
    0xa9e3e905, 0xfcefa3f8, 0x676f02d9, 0x8d2a4c8a,

    0xfffa3942, 0x8771f681, 0x6d9d6122, 0xfde5380c,
    0xa4beea44, 0x4bdecfa9, 0xf6bb4b60, 0xbebfbc70,
    0x289b7ec6, 0xeaa127fa, 0xd4ef3085, 0x4881d05,
    0xd9d4d039, 0xe6db99e5, 0x1fa27cf8, 0xc4ac5665,

    0xf4292244, 0x432aff97, 0xab9423a7, 0xfc93a039,
    0x655b59c3, 0x8f0ccc92, 0xffeff47d, 0x85845dd1,
    0x6fa87e4f, 0xfe2ce6e0, 0xa3014314, 0x4e0811a1,
    0xf7537e82, 0xbd3af235, 0x2ad7d2bb, 0xeb86d391,
};

static const uint8 md5_paddat[MD5_BUFLEN] = {
    0x80, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0,
};

static void md5_calc(uint8 *, md5_ctxt *);

void
md5_init(md5_ctxt *ctxt)
{
    ctxt->md5_n = 0;
    ctxt->md5_i = 0;
    ctxt->md5_sta = MD5_A0;
    ctxt->md5_stb = MD5_B0;
    ctxt->md5_stc = MD5_C0;
    ctxt->md5_std = MD5_D0;
    memset(ctxt->md5_buf, 0, sizeof(ctxt->md5_buf));
}

void
md5_loop(md5_ctxt *ctxt, const uint8 *input, unsigned len)
{
    unsigned int gap,
                i;

    ctxt->md5_n += len * 8;        /* byte to bit */
    gap = MD5_BUFLEN - ctxt->md5_i;

    if (len >= gap)
    {
        memmove(ctxt->md5_buf + ctxt->md5_i, input, gap);
        md5_calc(ctxt->md5_buf, ctxt);

        for (i = gap; i + MD5_BUFLEN <= len; i += MD5_BUFLEN)
            md5_calc((uint8 *) (input + i), ctxt);

        ctxt->md5_i = len - i;
        memmove(ctxt->md5_buf, input + i, ctxt->md5_i);
    }
    else
    {
        memmove(ctxt->md5_buf + ctxt->md5_i, input, len);
        ctxt->md5_i += len;
    }
}

void
md5_pad(md5_ctxt *ctxt)
{
    unsigned int gap;

    /* Don't count up padding. Keep md5_n. */
    gap = MD5_BUFLEN - ctxt->md5_i;
    if (gap > 8)
    {
        memmove(ctxt->md5_buf + ctxt->md5_i, md5_paddat,
                gap - sizeof(ctxt->md5_n));
    }
    else
    {
        /* including gap == 8 */
        memmove(ctxt->md5_buf + ctxt->md5_i, md5_paddat, gap);
        md5_calc(ctxt->md5_buf, ctxt);
        memmove(ctxt->md5_buf, md5_paddat + gap,
                MD5_BUFLEN - sizeof(ctxt->md5_n));
    }

    /* 8 byte word */
#ifndef WORDS_BIGENDIAN
    memmove(&ctxt->md5_buf[56], &ctxt->md5_n8[0], 8);
#else
    ctxt->md5_buf[56] = ctxt->md5_n8[7];
    ctxt->md5_buf[57] = ctxt->md5_n8[6];
    ctxt->md5_buf[58] = ctxt->md5_n8[5];
    ctxt->md5_buf[59] = ctxt->md5_n8[4];
    ctxt->md5_buf[60] = ctxt->md5_n8[3];
    ctxt->md5_buf[61] = ctxt->md5_n8[2];
    ctxt->md5_buf[62] = ctxt->md5_n8[1];
    ctxt->md5_buf[63] = ctxt->md5_n8[0];
#endif

    md5_calc(ctxt->md5_buf, ctxt);
}

void
md5_result(uint8 *digest, md5_ctxt *ctxt)
{
    /* 4 byte words */
#ifndef WORDS_BIGENDIAN
    memmove(digest, &ctxt->md5_st8[0], 16);
#else
    digest[0] = ctxt->md5_st8[3];
    digest[1] = ctxt->md5_st8[2];
    digest[2] = ctxt->md5_st8[1];
    digest[3] = ctxt->md5_st8[0];
    digest[4] = ctxt->md5_st8[7];
    digest[5] = ctxt->md5_st8[6];
    digest[6] = ctxt->md5_st8[5];
    digest[7] = ctxt->md5_st8[4];
    digest[8] = ctxt->md5_st8[11];
    digest[9] = ctxt->md5_st8[10];
    digest[10] = ctxt->md5_st8[9];
    digest[11] = ctxt->md5_st8[8];
    digest[12] = ctxt->md5_st8[15];
    digest[13] = ctxt->md5_st8[14];
    digest[14] = ctxt->md5_st8[13];
    digest[15] = ctxt->md5_st8[12];
#endif
}

#ifdef WORDS_BIGENDIAN
static uint32 X[16];
#endif

static void
md5_calc(uint8 *b64, md5_ctxt *ctxt)
{
    uint32        A = ctxt->md5_sta;
    uint32        B = ctxt->md5_stb;
    uint32        C = ctxt->md5_stc;
    uint32        D = ctxt->md5_std;

#ifndef WORDS_BIGENDIAN
    uint32       *X = (uint32 *) b64;
#else
    /* 4 byte words */
    /* what a brute force but fast! */
    uint8       *y = (uint8 *) X;

    y[0] = b64[3];
    y[1] = b64[2];
    y[2] = b64[1];
    y[3] = b64[0];
    y[4] = b64[7];
    y[5] = b64[6];
    y[6] = b64[5];
    y[7] = b64[4];
    y[8] = b64[11];
    y[9] = b64[10];
    y[10] = b64[9];
    y[11] = b64[8];
    y[12] = b64[15];
    y[13] = b64[14];
    y[14] = b64[13];
    y[15] = b64[12];
    y[16] = b64[19];
    y[17] = b64[18];
    y[18] = b64[17];
    y[19] = b64[16];
    y[20] = b64[23];
    y[21] = b64[22];
    y[22] = b64[21];
    y[23] = b64[20];
    y[24] = b64[27];
    y[25] = b64[26];
    y[26] = b64[25];
    y[27] = b64[24];
    y[28] = b64[31];
    y[29] = b64[30];
    y[30] = b64[29];
    y[31] = b64[28];
    y[32] = b64[35];
    y[33] = b64[34];
    y[34] = b64[33];
    y[35] = b64[32];
    y[36] = b64[39];
    y[37] = b64[38];
    y[38] = b64[37];
    y[39] = b64[36];
    y[40] = b64[43];
    y[41] = b64[42];
    y[42] = b64[41];
    y[43] = b64[40];
    y[44] = b64[47];
    y[45] = b64[46];
    y[46] = b64[45];
    y[47] = b64[44];
    y[48] = b64[51];
    y[49] = b64[50];
    y[50] = b64[49];
    y[51] = b64[48];
    y[52] = b64[55];
    y[53] = b64[54];
    y[54] = b64[53];
    y[55] = b64[52];
    y[56] = b64[59];
    y[57] = b64[58];
    y[58] = b64[57];
    y[59] = b64[56];
    y[60] = b64[63];
    y[61] = b64[62];
    y[62] = b64[61];
    y[63] = b64[60];
#endif

    ROUND1(A, B, C, D, 0, Sa, 1);
    ROUND1(D, A, B, C, 1, Sb, 2);
    ROUND1(C, D, A, B, 2, Sc, 3);
    ROUND1(B, C, D, A, 3, Sd, 4);
    ROUND1(A, B, C, D, 4, Sa, 5);
    ROUND1(D, A, B, C, 5, Sb, 6);
    ROUND1(C, D, A, B, 6, Sc, 7);
    ROUND1(B, C, D, A, 7, Sd, 8);
    ROUND1(A, B, C, D, 8, Sa, 9);
    ROUND1(D, A, B, C, 9, Sb, 10);
    ROUND1(C, D, A, B, 10, Sc, 11);
    ROUND1(B, C, D, A, 11, Sd, 12);
    ROUND1(A, B, C, D, 12, Sa, 13);
    ROUND1(D, A, B, C, 13, Sb, 14);
    ROUND1(C, D, A, B, 14, Sc, 15);
    ROUND1(B, C, D, A, 15, Sd, 16);

    ROUND2(A, B, C, D, 1, Se, 17);
    ROUND2(D, A, B, C, 6, Sf, 18);
    ROUND2(C, D, A, B, 11, Sg, 19);
    ROUND2(B, C, D, A, 0, Sh, 20);
    ROUND2(A, B, C, D, 5, Se, 21);
    ROUND2(D, A, B, C, 10, Sf, 22);
    ROUND2(C, D, A, B, 15, Sg, 23);
    ROUND2(B, C, D, A, 4, Sh, 24);
    ROUND2(A, B, C, D, 9, Se, 25);
    ROUND2(D, A, B, C, 14, Sf, 26);
    ROUND2(C, D, A, B, 3, Sg, 27);
    ROUND2(B, C, D, A, 8, Sh, 28);
    ROUND2(A, B, C, D, 13, Se, 29);
    ROUND2(D, A, B, C, 2, Sf, 30);
    ROUND2(C, D, A, B, 7, Sg, 31);
    ROUND2(B, C, D, A, 12, Sh, 32);

    ROUND3(A, B, C, D, 5, Si, 33);
    ROUND3(D, A, B, C, 8, Sj, 34);
    ROUND3(C, D, A, B, 11, Sk, 35);
    ROUND3(B, C, D, A, 14, Sl, 36);
    ROUND3(A, B, C, D, 1, Si, 37);
    ROUND3(D, A, B, C, 4, Sj, 38);
    ROUND3(C, D, A, B, 7, Sk, 39);
    ROUND3(B, C, D, A, 10, Sl, 40);
    ROUND3(A, B, C, D, 13, Si, 41);
    ROUND3(D, A, B, C, 0, Sj, 42);
    ROUND3(C, D, A, B, 3, Sk, 43);
    ROUND3(B, C, D, A, 6, Sl, 44);
    ROUND3(A, B, C, D, 9, Si, 45);
    ROUND3(D, A, B, C, 12, Sj, 46);
    ROUND3(C, D, A, B, 15, Sk, 47);
    ROUND3(B, C, D, A, 2, Sl, 48);

    ROUND4(A, B, C, D, 0, Sm, 49);
    ROUND4(D, A, B, C, 7, Sn, 50);
    ROUND4(C, D, A, B, 14, So, 51);
    ROUND4(B, C, D, A, 5, Sp, 52);
    ROUND4(A, B, C, D, 12, Sm, 53);
    ROUND4(D, A, B, C, 3, Sn, 54);
    ROUND4(C, D, A, B, 10, So, 55);
    ROUND4(B, C, D, A, 1, Sp, 56);
    ROUND4(A, B, C, D, 8, Sm, 57);
    ROUND4(D, A, B, C, 15, Sn, 58);
    ROUND4(C, D, A, B, 6, So, 59);
    ROUND4(B, C, D, A, 13, Sp, 60);
    ROUND4(A, B, C, D, 4, Sm, 61);
    ROUND4(D, A, B, C, 11, Sn, 62);
    ROUND4(C, D, A, B, 2, So, 63);
    ROUND4(B, C, D, A, 9, Sp, 64);

    ctxt->md5_sta += A;
    ctxt->md5_stb += B;
    ctxt->md5_stc += C;
    ctxt->md5_std += D;
}
